Chick acting strange- won't use feet

I have a 2 mos old silver Hamburg pullet who, until Monday night, appeared to be healthy.

She suddenly (somewhere between the hours of 8am-4pm) on Monday seemed to lose strength in her legs. The right seems to be more impacted, however, she does have control of both legs (no complete paralysis). She sits on her hocks and tries to stand, but she just falls over.

She has a good appetite, drinks well, and her poop is totally normal. I will even set her in the grass for a little and she munches it all down with no hesitation. She is mentally with it and has not ever seemed fuzzy through it all. She does not appear to be getting worse, but I have been supplementing her with electrolytes and vitamins.

No change in feed prior. They free range in the evenings when we get home.

It has been raining here quite a bit, but I try to keep them dry. However, when I went to change out their straw (bc it has been chilly at night), I found a solid sheet of white mold under the dry hay (our ground is so wet that it apparently seeping up through).

Can you check your vitamin label to make sure that it contains riboflavin. B complex tablets in the feed or water can also help. Riboflavin (vitamin B2) deficiency can cause sitting on hocks and curled under toes, eventually curled toe paralysis. You should know after a few days of treatment if that is the problem. mold can cause aspergillosis, a respiratory disease that can spread all over the body and brain. If you haven't seen gasping or other respiratory signs, it probably is not the mold. Were your chickens vaccinated for Mareks disease? That is sometimes a cause for lameness, and can progress to paralysis. Let us know how she reacts to the vitamins. Here is a good article about riboflavin deficiency: http://www.thepoultrysite.com/publications/6/diseases-of-poultry/217/vitamin-b2-deficiency/

Thank you for your input! I think you may be on to something here. She is not Marek's vaccinated, but I'm not leaning toward Marek's since there's been no change in status since Monday (I would expect more decline).

The Poly vi sol does have Riboflavin in it, but I have been giving her a very low does of the stuff. I went out and gave her an extra dose (much to her protest) not to long ago. Hopefully it helps!

The curling toes are quite distinctive. The photo with the chick sitting with one leg forward looks just like her positioning to. Thank you again so much! I will keep you posted on her status.

It's been since Monday, and she is still hanging in here. The weakness in her legs seems to have worsened a bit, but she is still eating/drinking like nothing is wrong.

I've got her on a lovely cocktail of Poly vi sol and Vit E/Selenium, but I'm not sure that the symptoms are reversible at this point. I'm just going to keep a low dose in her for the next few days and see what happens. Such a shame. Her eyes are bright and she's totally alert. Absolutely breaks my heart